1. FIELD OF THE INVENTION
This invention relates generally to apparatus for transporting successive work pieces to and from a working station at which a plurality of operations are performed thereon, and more particularly is directed to an improved apparatus, as aforesaid, in which the work pieces are printed circuit boards in which, for example, electronic parts or elements such as resistors, capacitors, IC elements and the like, are to be inserted or installed at the working station.
2. DESCRIPTION OF THE PRIOR ART
There is in existence an electronic part insertion machine which automatically supplies selected electronic parts from respective magazines or supply devices to an insertion device in accordance with a program which is predetermined by a control device, and in which the insertion device automatically inserts or installs the electronic parts delivered thereto in a printed circuit board which is located on a positioning table at a working station under the insertion device. In order to permit the fully automatic operation of such electronic part insertion machine, it is necessary to provide for the automatic transport of successive printed circuit boards to the working station from a suitable source or supply thereof, and further to provide for the automatic transport of each printed circuit board from the working station upon the completion of the insertion or installation of the electronic parts therein. Since the electronic parts are to be installed in each printed circuit board in various directions or orientations relative to the board, it is also necessary that each printed circuit board, while disposed at the working station, be rotated or turned in respect to the insertion device. Although an apparatus exists for transporting the printed circuit boards to and from the working station, as aforesaid, and such transport is effected without altering the shape, dimensions, quality and standardization of the successive printed circuit boards, the existing transporting apparatus is expensive to manufacture and maintain and is not readily adaptable to changes in the dimensions or shapes of the printed circuit boards which are to be transported or in the operations to be performed thereon at the working station. Furthermore, the possible operating speed of the autmatic electronic part insertion machine has been recently greatly increased by providing its control device in the form of a computer. However, the realization of such greatly increased operating speed of such computer controlled machine, and justification for the increased cost of the latter, have been impeded by the inability of the existing apparatus to transport the successive printed circuit boards to and from the working station at a rate commensurate with such greatly increased operating speed of the insertion machine. An existing computer-controlled electronic part insertion machine has also been provided with two heads or insertion devices for simultaneously inserting or installing selected electronic parts in printed circuit boards positioned at first and second working stations, respectively, but the existing apparatus for transporting the printed circuit boards is very expensive when applied to such machine having two heads.